Oklahoma City is 10 times larger than Topeka, Kansas.
Area: 1,682 km2 calculated
Oklahoma City is the capital and largest city of the U.S. state of Oklahoma. The county seat of Oklahoma County, the city ranks 27th among United States cities in population. The population grew following the 2010 Census, with the population estimated to have increased to 610,613 as of July 2013. Wikipedia
Area: 160 km2 calculated
Topeka is the capital city of the U.S. state of Kansas and the seat of Shawnee County. It is situated along the Kansas River in the central part of Shawnee County, located in northeast Kansas, in the Central United States. As of the 2010 census, the city population was 127,473. Wikipedia